Biomaterial Database

Appendix. Structural predictions on alpha 2-macroglobulin from the amino acid sequence. 1984

K G Welinder, and L Mikkelsen, and L Sottrup-Jensen

The composite result from three different methods predicts that alpha 2-macroglobulin has a predominant pattern of alternating beta-strands and turns. Only scattered pieces of alpha-helix are present throughout its sequence. Predicted beta-strands constitute 43.8% and helices 8.6%, in fair agreement with circular dichroism spectra. Circular dichroism spectra and sequence data suggest that the tertiary structure of complement component C3b is similar to that of the alpha 2 macroglobulin monomer. At present, the beta-barrel configuration of prealbumin seems to be a better model than those of soybean trypsin inhibitor, serine proteases, and immunoglobulins. A repetitive pattern of disulfide loops could indicate structural units of about 200 residues in size, but this is not supported by amino acid sequence homology. The hydropathic pattern of the sequence reveals numerous examples of predicted immunogenic peptides and detects an approximately 100-residue hydrophobic core region, which could constitute parts of the tentatively assigned consecutive activation cleavage and thiol ester domains. This core is an obvious candidate of rearrangement transfer between the highly exposed bait region and the partly shielded thiol ester site. The presumed intersubunit half-cystine is moderately buried and has two nearby patches of high charge density which could guide the dimeric assembling.

UI	MeSH Term	Description	Entries
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D004220	Disulfides	Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.	Disulfide
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000511	alpha-Macroglobulins	Glycoproteins with a molecular weight of approximately 620,000 to 680,000. Precipitation by electrophoresis is in the alpha region. They include alpha 1-macroglobulins and alpha 2-macroglobulins. These proteins exhibit trypsin-, chymotrypsin-, thrombin-, and plasmin-binding activity and function as hormonal transporters.	Slow alpha 2-Macroglobulins,alpha 2-Acute Phase Globulins,alpha-Macrofetoproteins,45S RNP,Acute-Phase alpha 1-Protein,Slow alpha 2-Globulin,alpha 1-Acute Phase Globulin,alpha 1-Acute Phase Protein,alpha 1-Macroglobulin,alpha 2-Acute Phase Globulin,alpha-Macrofetoprotein,Acute Phase alpha 1 Protein,RNP, 45S,Slow alpha 2 Globulin,Slow alpha 2 Macroglobulins,alpha 1 Acute Phase Globulin,alpha 1 Acute Phase Protein,alpha 1 Macroglobulin,alpha 1-Protein, Acute-Phase,alpha 2 Acute Phase Globulin,alpha 2 Acute Phase Globulins,alpha 2-Globulin, Slow,alpha 2-Macroglobulins, Slow,alpha Macrofetoprotein,alpha Macrofetoproteins,alpha Macroglobulins
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000939	Epitopes	Sites on an antigen that interact with specific antibodies.	Antigenic Determinant,Antigenic Determinants,Antigenic Specificity,Epitope,Determinant, Antigenic,Determinants, Antigenic,Specificity, Antigenic
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular